The Spinning Keep of Siri'wadjen was the magical structure surrounding the Calimemnon Crystal in which the genies Calim and Memnon were entrapped in the Calim Desert.1
The Spinning Keep magically hovered and rotated exactly 44 feet (13.5 meters) above the sands of the Calim Desert, just above the height that Memnon's disembodied essence could reach.1
The Keep was a twelve-sided hollow object made of crystalline stone.note 1 It was 70 feet (21 meters) across and was the color of translucent pearl.1 Like the Calimemnon Crystal within, the Keep itself was also built with elven high magic.2
There were three entrances to the Keep, each protected by an exceptionally challenging arcane locking puzzle. If solved, the panel would simply vanish, allowing one to fall into the Keep.1
The inside of the keep was simply an open space with no gravity.note 1 The Crystal floated at the very center. However, so powerful were the illusionary spells in effect within that an intruder was not likely to even recognize that he or she had passed through the keep walls successfully.1 The chamber was bitter cold, and the only light came from the Crystal.2
The Keep was surrounded by a powerful magical field that extended ten feet from every surface. This energy field repelled all non-living matter and elves, dwarves, and humans and reflected or absorbed all spells contacting it. Teleportation and scrying magics would not pass through the barrier,1 and trying to pass the spellward could result in one being teleported thousands of miles away.2
The interior walls were covered with razors,3 but these were hidden by the many illusion spells in place.2
The baelnorn Pharos still guarded the Crystal from inside the Keep, and he had the aid of genies and dozens2 of air elementals who were also bound to guard the gem. The defenders would attempt to blast any intruders back against the razor-covered walls.3
The high elf mage Pharos created the Keep as well as the Crystal within. By 1374 DR, it was nearly 9,000 years old2
Throughout the millennia of the Keep's existence, several persons have actually figured out a way to pass the Keep's magical barrier, solve its door puzzles, and view the Crystal, but none have ever touched the gem, as they were driven away by Pharos and the other guardians.3
"(From the year 1385DR)... A crisis of a different and more severe nature accompanied the Spellplague of a century past. This saw the fundamental laws of magic warped and changed, causing the destruction of the ancient Calimemnon Crystal. The mighty genies Calim and Memnon emerged and resumed their furious war, with all Calimshan’s people enslaved and its lands transformed into a battlefield. This was the second Era of Skyfire, which became more commonly known as the Genie Wars. " - Adventurers' Guide of Calimshan